Characterization of hepatitis E virus from sporadic hepatitis cases and sewage samples from Vellore, south India

Hepatitis E virus (HEV) is endemic in India and causes epidemics and sporadic cases. However, the exact transmission route for sporadic hepatitis E remains unclear. This study investigated HEV in sporadic hepatitis cases and sewage samples, as sewage is the major source of contamination of water in developing countries. Monthly sampling and testing for HEV in sewage samples from Vellore, India was carried out for 1 year (November 2009October 2010) and plasma and/or fecal samples from sporadic hepatitis cases presenting to a hospital in Vellore during 20062010 were tested for HEV RNA. A total of 144 raw sewage samples and 94 samples from sporadic hepatitis cases were tested for HEV RNA using RT-PCR. The prevalence of HEV RNA in sewage and sporadic cases was 55.6 and 9.6, respectively. HEV strains isolated from sewage showed 94100 nucleotide sequence similarity with the HEV strains isolated from the sporadic hepatitis cases. HEV RNA in sewage was identified more often during the summer (81.2) than the monsoon season (14.5) (p 0.001). This study indicates that sewage may be a source of contamination for sporadic hepatitis and also underscores the need for preventive measures to protect drinking water from sewage contamination, particularly in the summer. HEV strains isolated from this study were deposited in GenBank under accession numbers JF972766JF972773, JN705651JN705659 and JN705660JN705662.